Introduction: This study aimed to evaluate the sociodemographic factors, loss-related factors, and adult separation anxiety associated with a diagnosis of Prolonged Grief Disorder (PGD), after controlling for anxiety, depression, and perceived social support during the COVID-19 pandemic in Türkiye. Methods: Participants (n=126) completed an online survey that included socio-demographic and loss-related information, as well as the Hospital Anxiety and Depression Scale, Prolonged Grief Disorder Scale-13, Multidimensional Scale of Perceived Social Support, and Adult Separation Anxiety Questionnaire-27. Results: Twelve participants were diagnosed with probable PGD (9.5%). In the linear regression analysis, it was found that when the deceased person was a first-degree relative and younger in age, the presence of guilt, increased separation anxiety, and higher depression scores significantly associated with the severity of PGD. Conclusion: Even when the pandemic is under control, it remains crucial to offer mental health services those who have lost a loved one during the COVID-19 outbreak.